3H-Flupenthixol binding in post-mortem brains of schizophrenics: evidence for a selective increase in dopamine D2 receptors.
The binding of 3H-cis flupenthixol (3H-FPT) to dopamine receptors in membrane preparations from control subjects and schizophrenics was studied. Using a fixed concentration of 3H-FPT, no differences were observed between controls and all schizophrenics, although 3H-FPT binding was increased in schizophrenics who apparently were drug-free at the time of death. Scatchard analysis of 3H-FPT binding revealed that in drug-treated schizophrenics both the number of binding sites (BM) and the dissociation constant (KD) were increased, whilst in drug-free schizophrenics only the BM was increased. Using domperidone to differentiate 3H-FPT binding to D1 and D2 dopamine sites, it was found that only D2 sites were increased in drug-free schizophrenics. The results are discussed with reference to previous studies on dopamine receptors in schizophrenia, and the effects of neuroleptic treatment. It is suggested that a selective increase in D2 receptors may be associated with the disease process in schizophrenia.
D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D002421:Caudate Nucleus / Q000378:metabolism; D005475:Flupenthixol / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011954:Receptors, Dopamine / Q000378:metabolism*; D012559:Schizophrenia / Q000378:metabolism*; D013892:Thioxanthenes / Q000378:metabolism*
D011954:Receptors, Dopamine; D013892:Thioxanthenes; D005475:Flupenthixol